Sound device



April 4, 1939. w EAVES 2,153,500

SOUND DEVICE Filed March 18, 1936 INVENTORY WILLIAM C. EA vEs ATTORNEYSPatented Apr. 4, 1939 4 UNITED "STATES.

PA-TENT [oi-"Flea I souN'n navrca William C. Eaves, Elmhnrst, N.

Y., as'signor c1 glfly per cent to (fiarl E. Fowler, New York,

Application March 1a, 1936, Serial No. chase- My inventionrelates toasound or signal device. Sound devices have heretofore been contemplatedin which there is a fixed grid or plate and a movable plate or gridpositioned'over said fixed grid, together with means-for vibrating themovable grid so as to modulate .the fiow of air through said grids whencompressed air is applied to the grids. Such devices, while beingcapable of producing various sounds depending upon the characteristicscompressed air to produce sound waves is practically unlimited.

It is a further object to provide a sound device of the characterindicated in which the sound to be, produced may be readilypredetermined and which wear is reduced to a minimum in which variationsduced. 4

Another object is to provide a device of the character indicated, inwhich the volume of sound produced may be readily predetermined andcontrolled.

Anotherobject is to provide a sounddevice in and in which the mechanismitself is substantially vibramay be very readily protionless and quiet.

A furtherobject is to provide a sound device in which a movable gridmember is substantially balanced.

A further object is to provide -a sound device ofv the air modulating orgrid' type, together with an intensifying grid.

Another object is to provide a movable grid type device which isexceedingly economical in power for operating the same and economical ofair.

Still another object is to provide a novel form of simple, compact, selfcontained sound device. Other objects and features of invention will behereinafter pointed out or will become apparent to those skilled in theart upon a reading of the specification in connection-with the drawing.In the drawing which of the grids, speed of'vib'ration, etc., have aconsiderable number of limitations, 1

shows, for illustrative 1 purposes only, preferred forms of theinvention-- Fig. 1 isa longitudinal, sectionalview through a sounddevice, illustrating features of the invention;

Figs. 3, 4 and 5 are views in elevation of grids which may be fixedgrids;

Figs. 6 and 7 are views in elevation of two different grids which may berotating grids;

Figs. 8 and '9 are views in elevation of relatively rotatable grids inwhich the grid shownin Fig. 8 may be a fixed grid; and

Figs. 10. and 11 are views respectively similar .to Figs. 8 and 9,illustrating other forms of grids. 15

In the form shown in' Fig. 1, which is merely an illustrative drawingrather than a commerciallypracticable form of device so far as concernsthe casing, at least, 5 represents a housing or casing in which ismounted a motor 8 of any suitable type, such as an electric motor, forrotating the shaft 1. 8 indicates an air compressor cylinder in whichthe compressor rotor 9, carrying blades, is mounted. The rotor 9 iscarried by the shaft 1, as will be understood, and when the shaft isrotated air will be taken in through the inlet l0 and discharged throughthe outlet II and pastthe-cock l2 into an chamber. l3, which, in theform illustrated in Fig. 1', is ina part of the main housing 5. Themotor, pressor and shaft 1 are preferably motiznted on deep race ballbearings iL-Il, so as reduce friction to a minimum and so as to sustainthe end thrust loads on the shaft 1. The housing 5 is provided with anopening I 5 for mounting grids .forming an important feature of myinvention. In the form shown l6 represents a fixed grid mounted intheopening l5 and which may be held in place by means of a base" ingfriction between those two grids, particularly .50

should the rotatable grid be fiexedunder pressure, I prefer to provide asubstantialpressure sustaining grid 20, which is mounted in fixedposition relatively to the grid 5,- so that the rotatable grid I! mayrotate between the grids I6 55 v Fig. 2 is a view similar to Fig. i butilliis'trat- 5 ing a slight modification;

com- 30 [8 of suitable type and de- 40 and 20 and have merely a runningfit or be perfectly free of the two fixed grids during rotation. It willbe observed that with compressed air in the chamber II, when therotatable grid I9 is rotated air will-flow through the grids when theopenings therein'come into registry with each other and the fiow will becut oil when the openings are out of registry. By thus modulating theair flow sound waves are set up and are emitted from the horn l8 and thevolume; intensity and other characterlsticsof the sound emitted willdepend on a number of factors, including size and number of gridopenings, spacing of grid openings, speed of rotation, air pressure andpossibly some other factors. i k I The form shown .in Fig. 2 may beconstructed in substantially the same manner as that shown in Fig. 1,except that compressed air is supplied to the chamber l3' through acompressed air inlet 2| from'some outside source. In the modificationshown in Fig. 2 I have provided a substantial bearing 22 on a web in theair chamber and located in close proximity to the rotating grid 23.

In the form shown in Fig. 2 the balancing or pressure sustaining grid 20has been omitted but it is to be understood that it may be employed ifdesired. Otherwise the operation ofthat form shown in Fig. 2 is the sameas that of Fig. 1. I

While the sound waves are generated by the modulation of the air inpassing the grids and in the horn, I prefer to employ what may be termedan intensifying grid 24, slightly spaced from the grids on the. hornside thereof so as to provide a chamber 25. The air modulations or wavesproduced by the relatively fixed and rotating grids are impressed uponthe body of air in the chamber so that the puffs of air instead ofsetting up local vibrations in the horn directly in a front of thegridopenings vibrate the body of air in the. chamber 25 and thevibrations are transmitted through the grid openings in the intensitygrid 24 and a more extensive wave front is produced in the horn.

It should be noted that the variations possible with my sound device arealmost infinite. For

example, if a fix ed grid as shown in Fig. 5, that is, with a singlegrid opening 38, be employed, to-

gether with a rotating grid as shown in Fig. 6

having a single grid opening 3 I it will be observed that for eachrotation 01 the shaft 1 there will be one passage of air through thegrid openings iI-ll. The number of modulations will therefore be one perrevolution and by varying the speed of the rotating grid the number ofmodulations may be varied at will. Furthermore, if a rotating grid asshown in Fig. 6 be employed with a fixed, grid as shown in Fig. 3, thatis, with two diametrically spaced grid openings"3233,

there will be two modulations for each rotation of the shaft 1 and themodulations will be equally spaced, not only during each revolution ofthe shaft but equally spaced. per second and there willbe twice thenumber of modulations'per second as would be produced with the singlegrid opening 36, as in Fig.5. Iithe fixed grid shown mm. 3 be modifiedas shown in Fig.4 so as to have in addition to the diametrically spacedopenings 32'43' corresponding to openings inthe arid otl'lg. 3,. threeadditional grid openings Ska-l6, it will be seen that in addition to themodulations produced by the grid openings li -.33 tions produced'by thear d openings -35-36. Thle modnlaflons produced by the combination ofgrids of Figs. 4 and 6 will befive per-'reyolw efiect of the firstimpressed wave.

' ing modulation of the air pletely closed. If

there will be three additional modula-- rate of modulation perrevolution will be four times what it would be for equally spaced grid 5openings. The characteristics of the sound waves produced may be variedat will by various spacings of the grid openings while maintaining therate of rotation of the rotatable grid fixed. With the same number ofgrid openings equally spaced circumferentially, the number ormodulations per second will be a given number and with the same numberof grid openings but unequally spaced, the number of modulations persecond will be the same, but during each revolution the rate ofmodulation for unequal spacings will be varied and the sound effectsproduced will be different. By proper spacing and sizing of the openingsit is even possible to modulate the air so as to produce a sound waveand to immediately thereafter and with the properlag produce in effect afortifying wave to enhance the sound In the examples heretofore given,we have assumed only a single opening 3| in the rotating grid. Furthervariations can be made by increasing the number and spacing of the gridopenings in the rotating grid, all without changing the speed ofrotation thereof. Still further variations may be attained for anyselected number and spacing of grid openings by variations in the speedof the rotatable grid.

In the grid form. shown in Figs. 3 to 6 it will be noted that the gridopenings are generally of sector form, that is, the side edges of theopenings extend radially. Such grid formation produces a sharp openingand sharp closing of the grid openings with consequent effect on the airmodulations produced. In the form of rotatable grid shown in Fig. '7 thegrid openings 3? are all parallel to each other and with such a rotatingrid there will be in efiect a continuous undulate with consequenteffect upon the sound waves produced. The opening and closing ofthe gridopenings will not be sharp as with radial openings but will be gradualon the opening and trailing or wire drawing on the closing if, in fact,the grid openings are ever coma fixed grid of the same form as therotating grid of Fig. 7 be employed, there may be a distinct cut-ofiwhen the openings of the fixed and rotatable grids are out of registrywith each other, and immediately the rotatable grid is rotated, therewill be a gradual opening and a rather prolonged closing or wire drawingso as to cause what may be termed an intermittent undulating modulation.A fixed grid of'a type similar to that of the rotating grid of Fig. '7is shown in Fig. 8, that is, the fixed grid is provided with a parallelchordal opening 38. The grid openings of Fig. 8, considered as a whole,may be considered as a pair of radial grid openings but modified so asto form by the chordal lands or partitions extending thereacross. Aretating grid of the type shown in Fig. 9 may be employed with a fixedgrid as shown in Fig. 8.

The rotating grid of Fig. 9 is provided with two oppositely spacedrelatively large radial open-' ings 39-39.

grid openings ll in the first quadrant and a plu- 15 rality of smallequally spaced grid openings 42 presures and the intensity and volume ofthe in the third quadrant. 'The relative spacing of the openings 4| aredifferent from the relative spacings of the openings 42. The rotatablegrid has corresponding openings designated the same as-those in Fig. '10distinguished bythe prime.

When the rotatable grid is superposed on the fixed grid in the relativepositions shown, all of the grid openings will be in registry and whenthe rotatable grid rotates clockwise, there will be a sharp cut-ofl" ofthe major grid openings 40-40 and subsequently there will be acontinuous or intermittent grid opening of lesser extent when the majorgrid openings 40' pass over the minor grid openings ll-42, so that themodulating efiect may produce what may be termed a powerful wave andreinforced by minor waves during the first quarter rotation and stillfurther modification during the third quarter rotation when aftera'relatively' powerful modulation .01- Wave production at the end of thesecond quarter revolution, the grid openings 52' in sequence pass overthe openings ii and the. relatively wider spaced grid openings 48' passover the relatively closer spaced openings 52.

The few grids herein described will be Suficient to indicate to thoseskilled in the art the very great number of variations which may beproduced by varying the size, extent and circum ferential spacing ofgrid openings in either the V fixed or rotating grid, or in both, and itmay be noted that an almost infinite number of further variations may bemade by variations in the speed of rotation of the rotatable grid andsuch speed could, of course, be effected by the relative rotation of thegrids, that is, by rotating both the rotatable grid and what I haveherein termed the fixed grid, in either opposite or the same directionat various speeds. It is further to be noted that there is practicallyno limit to the speed of modulation possible with my improved device andwaves may be impressed so as to go beyond the range of audiblefrequences. Such fre quencies may be valuable in sound or signaltransmission in that such high frequency waves may be picked up andmodified at the receiver, so as to come an audible range. Furthermore,it will be seen that with relatively rotating grids there will be littlewear or vibration regardless of the speeds, and the grids may be sobalanced and counterbalancedas torreduce vibration to a negligiblequantity even at very high Speeds.

Sounds of any desired characteristics may be produced-and apredetermined sound may be produced by variations in the grid forms andspeeds of rotation.

The device-will operate with high or low'uir,

relatively little leakage and the efilciency will be high and the deviceeconomical of air and power for rotating the grid. By bringing therotary grid up to full speed before supp y ng the air under pressurewill produce sharp sounds, otherwise a trailing eiiect will be produced.By the term air as used herein I desire to include any gas or vaporcapable of use for sound production.

While the invention has been described in considerable detail and a fewillustrative forms shown, it is to be understood that various changes,modifications, additions and omissions may be made within the scope ofthe invention as defined in the appended claims.

i. In a device of the character indicated, relativeiv movable grids forcausing a flow 0! air passing through said relatively movable grids tobe modulated thereby, and an intensity grid substantially spaced fromsaid relatively movable grids so as to leave a substantial body of airbetween said intensity grid and said relatively mavable grids, wherebyvibrations impressed upon said body of air may be transmitted throughsaid intensity grid upon a more extensive wave front than that producedby said relatively movable ids.

2. In a device of the character indicated, rein-- tively rotatable gridshaving a running lit with each other for causing a flow of air passingthrough said relatively rotatable grids to. be modulated thereby, and anintensity grid subsstantially spaced from said relat vely rotatablegfldssoastcleaveasubstantlalbodyofa'irbetween said intensity grid andsaid relatively rotatable grids, whereby vibrations impressed uponrotatablegrldshavingopeningsthereinandln communication with said storagechamber, and

meansforrotatlngoneotsaid'grldsandactuatingsaidpumplnsaidpumpchambm-WIIIIAHC.IAVB

